Lorex IP wired cameras equipped with alarm I/O functionality typically include a 5-wire cable for connecting external devices (e.g., sensors, sirens, strobe lights). These alarm wires allow the camera to:
- Detect signals from external devices (Alarm Input)
- Send signals to external devices (Alarm Output)
Alarm Wire Details (Typical Color Code)
| Wire Color | Function | Description |
|---|---|---|
| Red | Power (12V Out) | Supplies 12V (max 300 mA) – can power low-consumption sensors |
| Black | GND (Ground) | Common ground for all alarm connections |
| Green | Alarm Input | Receives trigger signals from external sensors (e.g., door/window sensor) |
| White | Alarm Output | Sends signal when an event is triggered (e.g., motion detection) |
| Blue | Reserved/Mode B | Use Optional – used for custom or secondary outputs |
How Alarm Input Works
Step 1: Connect an external sensor to the Alarm Input (Green) wire.
- The camera interprets voltage levels:
- Logic "1" (HIGH) → Signal between +3V to +5V, or idling
- Logic "0" (LOW) → When the signal is grounded
- Use GND (Black) wire to complete the circuit.
+3V to +5V or Idle ──┐
├────▶ [ Green - Alarm Input ]
Ground ─────────┘
↓
[ Camera Logic ]
Logic "1" if HIGH
Logic "0" if LOW (Grounded)
How Alarm Output Works
Step 2: Connect to the Alarm Output (White) wire based on your application.
The alarm output is an open-drain (OD) design, which supports two modes:
Mode A: Level Output Mode
- Requires an external pull-up resistor (10kΩ typical)
- Output voltage max: 12V
- Current max: 300 mA
- Pull-up to HIGH level when alarm not active
- Pulls LOW (to GND) when alarm is triggered
Diagram: Mode A
[ External Device ]
│
+12V ─────────────┐
│
[ Resistor ]
│
[ White - Alarm Output ]────▶ [ Camera ]
│
[ Black - GND ]
Mode B: Switch Output Mode
- Acts like a switch to control external devices
- Connects external power through the Alarm Output (White) when triggered
Diagram: Mode B
[ Power Supply +12V ]
│
[ Alarm / Siren ]
│
[ White - Alarm Output ]────▶ [ Camera ]
│
[ Black - GND ]
Use external relay if your device exceeds 12V or 300 mA.
Configuring Alarm I/O in Web Interface
Step 3: Access via web browser:
- Login to the camera's web interface
- Go to Alarm Settings
- Configure:
- Alarm Input:
- Choose mode:
- NO (Normally Open): Default, LOW = "0"
- NC (Normally Closed): HIGH = "1"
- Choose mode:
- Alarm Output:
- Toggle based on events (e.g., motion, smart detection)
- Alarm Input:
Summary of Setup
| Feature | Input Signal | Output Behavior |
|---|---|---|
| Input Logic | HIGH (3-5V) or GND | Reads Logic 1/0 |
| Mode A Output | Pull-up resistor | OD Output, switches LOW |
| Mode B Output | Acts as a Switch | Connects circuit to GND when triggered |
Pro Tips
- Use shielded wires if running over long distances.
- Double-check maximum load (12V, 300 mA) to prevent damage.
- Secure all connections with screw terminals or wire nuts.
- Isolate power supplies to avoid ground loops.
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